1,3,13,31,33,313,133,331,333,1333,3133,3313,3333那个是合数?
问题描述：
1,3,13,31,33,313,133,331,333,1333,3133,3313,3333那个是合数?
答
33=3*11
333=3*3*37
1333=31*43
3133=13*241
3333=3*11*101
一共有33,333,1333,3133,3333